Signaling system



Jan. 4, 1944.

W. H. T. HOLDEN sGNALING SYSTEM Filed June 27, 1942 4 Sheets-Sheet 1 /m/E/v To@ WH 7.' HOL DEN y @WNW www;

A from/Ey Jan. 4, 1944. w. H. T. HOLDEN 2,338,434

SIGNALING SYSTEM Filed June 27, 1942 4 Sheets-Sheet 2 OOOO OOOOOOOOOOOOOO OOOOOOOOOO/OOOOOOOOOOOOOOOOOOO O o O o 204 O O 8 ooooooooooooooooooooooo 000000000000 L J f----Q 200 20/ y 202 203 245 /M/E/vro/P WH 7THOLDE N ATTORNEY Jan. 4, 1944.

H. T. HOLDEN 2,338,434

SIGNALING SYSTEM Filed June 2'7, 1942 4 Sheets-Sheet 4 A 7` TORNE Patented Jan. 4, 1944 SIGNALING SYSTEM William H. T. Holden, Woodside, N. Y., assigner to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporationv of New York Application June 27, 1942, Serial No. 448,731

8 Claims.

This invention relates to electric signaling, particularly when employed in connection with the operation of automatic telephone systems.

An object of the invention is to facilitate the identication of lines, trunks, or other electrical circuits or devices.

Another object is to increase the eiiiciency of the identifying equipment by utilizing a common signaling mechanism for obtaining the identity of a plurality of lines concurrently.

These and other objects of the invention are realized in a system comprising a plurality of identiers which may be connected concurrently to calling lines in the group, and in which a plurality of signal lamps, one for each of the lines, are arrayed in a denite order with respect to the designations of the lines and serve to energize selectively the photoelectric cells of a group, which in turn operate the connected identifiers to establish therein the digital characters -oi the associated lines. More specically, said identiners are provided with an impulse generator which produces impulses of a plurality of different phases,each phase characterizing a different one of said identifiers, each identier serving to transmit impulses of its characteristic phase to ash the particular lamp in said array representing the line to which the identier is connected, the impulses of all phases produced by the photoelectric cell in response to the flashing lamps being delivered to all of said identifiers simultaneously, and each identifier being provided with means selectively operative in response to .inipulses of its own characteristic phase delivered thereto by the photoelectric cells to establish in said identifier the designation of the calling line connected thereto. The advantage of this identifying arrangement is that the iield of signal lamps representing all oi the lines in a telephone office may be utilized to identify a plurality oi lines that are'in a calling condition simultaneously.

A feature of the invention is a system of this character in which the light from the lamps in the common field or array is conducted to the photoelectric cells, which represent the Various digital values of all digit places in the line designations7 by means of light-conducting elements associated with ythe lamps in the eld in accordance with the digital place values. More specifically plates of light-conducting material are associated in the field of lamps in such a Way that the light from the lamps of all lines having the same character value in each digital place of the designations is collected bythe associated plate and conducted to the phctoelectric cell which also represents the same character value of the same digital place.

These and other features of the invention will be discussed more fully in the following detailed specification.

In the drawings accompanying the speciiication:

Fig, 1 is a conventional diagram of an automatic telephone system arranged for calling line identiiication Fig. 2 illustrates the field or panel of lamps representing the subscribers lines in an omce and serving to identify the lines by their numbers;

Fig. 3 illustrates the eld of lamps together with the associated light transmitting plates for conducting the light from said lamps to the photoelectric devices;

Fig. 4 is an end View of the lamp panel taken along the line 1 -lof Fig. 3;

Fig. 5 is an enlarged sectional View of the lamp panel taken along the line 5 5 of Fig. 3;

Fig. 6 is a plan View of one oi the light-conducting plates of the panel assembly; and

Fig. 7 is a perspective view of the light-conducting plates.

rlvhe present invention is particularly usefulin systems that require the preparation of tickets ior the Vpurpose of assessing a calling telephone subscriber iorconversations held with other subscribers. Since these tickets are prepared vautomatically, it is necessary to determine the nurnber of the lcalling line in order Athat the charge may be assessed against the proper party. However, the invention may be used in any type of system where it is desirable to determine automatically the identity of a line, trunk, circuit, or other device. For example, it is often desirable to display the number of a calling party before an operator to whom the line has been extended, thereby eliminating .the necessity ior the operator to make an oral request `or to perform a number-checking operation.

Referring to Fig. l of the drawings, the automatic telephone system illustrated herein com prises a large group of lines, usually ten thousand, which appear in the telephone central oilice in non-numerical switches such as finder switches. The line Iil, for example, appears in the bank of line `finder switch F whichin turn is associated with a rst selector switch S. The selector S may have direct access to outgoing trunks, orit may have access through a succeeding selector switch S-I to these outgoing trunks, such as the trunk 10|, extending to distant oiices.

The designation or identify of each line that establishes a toll call over one of the outgoing trunks |01 is obtained by selectively conducting the light from any lighted lamp in the eld to a series of lphotoelectric cells representing the digital values of the line designation corresponding to the lighted lamp. To this end four sets of light-conducting plates are associated with the eld of lamps, said sets representing respectively the four digital places of the line designations.

Before proceeding further with the description of the light-conducting plates, an explanation will be given of the numerical arrangement ofthe signal lamps in the eld. Referring to Fig. 2, the lamp eld here illustratedw comprises ten thousand signal lamps, onev for each subscribers line in the oiiice. These lamps are arranged in decimal order in coordinate horizontal and vertical rows, there being one hundred horizontal rows and one hundred vertical rows, each row in both directions containing one hundred lamps. The hundred vertical rows are divided into ten equal groups, one for each thousand lines. For example, the vertical groups 200, 20|, 202 and 203 represent the No. 0, No. 1, No. 8 and No. 9 thousands groups of lines, and the six intermediate groups of lamps not shown in the drawings represent the corresponding thousands groups. Each one of these thousands groups contains ten vertical rows of one hundred lamps representing respectively the ten hundreds groups in the thousand. In like manner the eld oi lamps is divided into ten horizontal groups representing the ten tens groups of all hundreds groups. For example, the horizontal groups 204, 205, 206, 201 and 208 represent respectively the No. 0, No. 1, No. '1, No. 8 and No. 9 tens groups. Each of these tens groups contains ten horizontal rows of lamps representing respectively the ten different values of the units digit.

Returning now to the light-conducting platesv associated with the lamp eld and referring particularly to Figs. 3 to '7, it will be noted that there are ten of these plates 209, 2H), 2H, 212 representing the ten diierent values of the thousands digit. The plate 20S, for example, representing the No. thousand, covers the entire thousands vertical group of lamps 200. Furthermore, the plate 209 is provided with one thousand hcles coordinately arranged coincident with the coordinate arrangement of the lamps in this thousands group. In fact the lamps, when in place, project through the holes in the plate 209 and also through the holes in the associated plates as will be explained hereinafter. The plate 2 l2 covers the lamps in the No. 9 thousands group 203 and is'likewise provided with coordinate rows of holes for receiving the lamps in this group. Similarly there are eight intermediate light-conducting plates corresponding to the eight intermediate thousands groups of lamps. The ten thousands Iplates 209, 2M. 2li and .2!2 lie in the same plane and constitute the iirst layer of the light-conducting plates, as seen more clearly in Figs. 4 and 5. Thus when ani7 lamp in any thousands group is illuminated the light from said lamps enters the associated thousands plate and is conducted by said plate to an exit point where it is caused to shine on an associated photoelectric cell. The ten thousands plates 2&9. 2li? and 2!2 are provided with the respective light exit points 2I3, 2M. 2l5. and all other surfaces of these plates. with the exception of the surfaces in the holes adjacent the signal lamps, are covered with an opaque paint or other substance to prevent the escape of light. In other words, any light entering the medium of the plate from the signal lamp is conducted through the plate and emerges at the exit point. These plates are preferably made of some material having a relatively high light-conducting property.

There are also ten tens light-conducting plates similar in size and shape to the thousands plates but arranged in the assembly at right angles thereto. The No. 0 tens plate 2 I6 covers the No. 0 tens group of lamps 204 (Fig. 2) and contains one thousand holes arranged in coordinate rows and in registration with the corresponding holes in the thousands plates 209, 2I0, etc., for receiving the lamps. The tens plates 211, 2I8, 2|9 and 220 relate respectively to the No. 1, No. 7, No. 8 and No. 9 tens groups, the intermediate plates not being shown in the drawings. As seen in Figs. 4 and 5 the tens plates occupy the second layer in the assembly. Thus the light from any one of the thousand lamps in a particular tens group is conducted by the associated plate to the light exit point for application to a photoelectric cell. To this end the tens plates are provided with the light exit points 22|, 222, 223, 224.

There are also ten light-conducting plates for the ten different values of the hundreds-place digit. It is necessary, however, to shape these plates like a comb, as seen in Fig. 6, for the reason that each value of the hundreds digit is represented by a row of one thundred lamps in each of the ten thousands groups. More specically, the hundreds plate 225, which represents the No. 0 value oi the hundreds place digit, has one strip or tooth 226 covering the single row of lamps in the No. 0 thousands, a strip 221 covering the single rows of lamps in the No. 1 thousands, and so on for each of the remaining thousandsgroups, including the last strip or tooth 228 which covers the single row of lamps in the No. 9 thousand having the No. 0 hundreds digit. The next hundreds plate 232 represents the No. 1 hundreds digit and is therefore provided with ten strips 229, 230, 23|, covering respectively the ten vertical rows of lamps in the ten thousands groups having the hundreds digit 1. And likewise the eight remaining horizontal plates 233, 234, 235, 238, 239 are provided with strips which are similarly disposed with respect to the vertical rows of lamps in the assembly. The hundred teeth or strips 225, 221, 228, 229, 230, 23! on the ten hundreds plates are disposed in a single plane in the lamp assembly constituting the third layer as seen in Figs. 4 and 5. To accomplish this arrangement the body and the teeth of the No. 0 hundreds plate 225 all lie in the same plane as seen in Figs. 4 and 6, but the teeth on the remaining nine plates are offset with respect to the bodies of the plates by progressively increasing amounts as best seen in Figs. 4 and 7. For example, the ten strips including the last two, 240 and 24 I, on the lowermost or No. 9 plate 230 are iirst turned up at right angles of the body of the plate and are then turned over again at right angles to permit the perforated sections of these ten strips to occupy a single plane in the lamp assembly. Like the others, the hundreds plates are provided with exit points 242, 243, 244, 245.

Finally there are ten units plates 246, 241, 248, 249, 250, which are shaped like the hundreds plates, each being provided with ten strips or teeth covering the ten horizontal rows of lamps in the field having the same value for the units digit.

For example, the No. units plate 246 is provided with ten teeth 25|, 252, 253, 254 which cover respectively the ten horizontal rows of lamps in the ten tens groups having the No. 0 units digit. Like the hundreds plates, the hundred strips ol' the ten units plates are all disposed in the same plane in the lamp assembly, this plane constituting the fourth layer as seen in Figs. 4. and 5. Also the units plates are provided with exit points 255, 256,251, 258, 259.

The four layers of plates above described are mounted upon a suitable base or" insulating material 265, which also contains the sockets for the thousand signal lamps 25|, 252, 253. Asabove explained, the holes in all of the plates are in registration to receive' thev lamps, which are suitably shaped for that purpose, and all surfaces or all plates are covered with some opaque material, except the surfaces Within the holes which receive the signal lamps. lIt will now beseen that any illuminated lamp in the array causes its light to enter a combination of four conducting plates, depending upon the location of the lamp, and the light entering these four plates is conducted selectively thereby to the four corresponding exit points. Since these four exit points characterize the four designation digits of the lighted lamp, it is possible to translate these light signals through photoelectric means into currents that may be utilized to register the designation of the associated line. It was mentioned hereinbeiore that the light-conducting plates are preferably made of material having high conducting properties; and it will be understood that the conductivity oi these plates is so high relative to the conductivity of the signal lamp envelopes that no detrimental effect results from the leakage of light.

The lamp panel assembly shown in detail in Figs. 2 to 7 is provided in the central oce of a telephone system, such as the one illustrated .in Fig. l, and includes a signal. lamp for each. of the ten thousand lines of the oiiice. Four of these signal lamps Iill., IllB, IM and i615 have been illustrated in Fig. l, the remaining lamps and the light-conducting plates being omitted for the sake ci simplicity. As will be explained hereinafter, the signal lamps in the lamp panel are designed to illuminate and extinguish in response to rapid impulses applied to them over the operating circuits. Accordingly, these lamps are preferably of the gaseous discharge type, although any type of lamp may be used which is capable of following impulses or the required speeds.

Four sets of photoelecric cells or other lightsensitive devices !05, lill, lilo and |239 are also provided in the central office and are associated with the light-conducting plates in the lamp panel assembly for the purpose of receiving the light selectively conducted from any lighted lamp in the panel. There are, it will be remembered, four sets of these light-conducting plates, each set comprising ten plates and each plate having a single light exit point. Accordingly, the group of photoelectric cells |06 represents the thousands digital place and comprises ten individual cells, one for each of the ten values of the thousands digit. These ten individual cells are located, as illustrated in Fig. 6, respectively in proximity to the exit points of the corresponding plates or the thousands group. Similarly the hundreds group of cells iil'l comprises ten separate cells which are located respectively adjacent the light exit points of the ten hundreds light-conducting plates. And the saine is true of the ten photoelectric cells l 5S of the tens group ander the ten cells |58 of the units group;

The central electrodes of all forty of the photoelectric cells are connected in multiple to the positive pole of battery H0, and the outer electrodes of the forty cells are connected respectively to forty multiple conductors of the group H3 which comprises a connecting medium between the cells and a plurality of number identiers III, H2, etc., the multiple medium H3 is divided into four sets of conductors H4, H5, I I6 and HI corresponding to the thousands, hundreds, tens and units places. Accordingly the set I4 includes ten conductors which are connected respectively to the ten photoelectric cells H8', H9 in the group |55. Similarly there are ten conductors in the set I l5 which are connected respectively to the ten cells in the hundreds group lill. And in like manner the ten conductors of set H5 and the ten conductors of set I |I are connected respectively to the cells of the tens group IBB and to the cells of the units group |59.

Each of the line identifiers, such as the identi- Iier I I I, includes a series of forty space discharge tubes which are connected respectively to the forty conductors of the multiple group H3. Only two of these tubes, tube |25 of the thousands set and tube |2| of the units set, are illustrated, but it will be understood that the remaining thirtyeighttubes are provided and are connected similarly to the appropriate conductors of the multiple group I I3. The rst ten tubes, including the tube |20, represent the ten values of the thousands digit, and their control grids are connected respectively to the corresponding conductors of the thousands set I lll. The next ten tubes represent the hundreds digit values and are connected to the ten conductors o the hundreds set H5. The third set of forty tubes represents the tens digit values and is likewise connected to the respective conductors of the tens set H5. Finally, the last set of ten tubes, including the tube |2I, represent the units digit values and are connected respectively to the corresponding conductors of the units set Hl'. The identifier III is also provided with a series of forty discharge tubes |22, |23, one for each of the tubes |25, I2I., and also with forty associated register relays |24, |25. The register tubes |22, |23 are connected through individual transformers |25, |21 to the anodes |28, |29 of the tubes |25, IZI. The supressor grids itil, le! of the forty tubes l2! are connected in multiple over conductor |32 to secondary winding of a common transformer |33. The screen grids |34, |35 are connected to the positive pole of the anode battery, and as above noted, the control grids |36, |31, are connected through condensers |35, |35 to the multiple conductors H3.

Each of the remaining identiers in the oice, such as the identifier H2 illustrated conventionally, is similarly equipped and connected in multiple to the common connecting medium I |3.

The ofce is also provided with an impulse generator M9 which is energized by a source of alternating current lill and which produces in its output leads impulses of different phases in each successive cycle of the source Ifl l. The successive phases are assigned respectively to the different identiers H l, I l2, etc., so that i o pulses of a characteristic phase are supplied by the generator Illl to each identifier. For example, impulses of phase No. 0 are supplied over lead |42 to the identier IH, impulses of phase No. l

are supplied over lead |43 to identifier ||2, and impulses of other phases are supplied to other identiers Vnot illustrated in the drawings. The impulse generator may be of any suitable type such as those disclosed in Holden Patents 2,324,394 of July 13, 1943, 2,252,766 of August 19, 1941, and 2,285,815 of June 9, 1942.

Thus all of the identiers in the oiiice are permanently connected over the common connecting medium IIS to the photoelectric cells associated with the signal lamp panel. The usual connecting switches which serve to connect one of a plurality of equivalent devices with a common mechanism to the exclusion of the others have been dispensed with by the use of this common connecting medium and a signaling method in which impulses of different phases are used. Accordingly, the identiiication of a plurality of diierent lines may take place concurrently, all

of said lines making use of the same lamp panel, g'

without any interference between them. Each connection that is established seizes one of the identiers for association therewith, and all identiers in concurrent use are capable of receiving signals from the lamp panel over the common medium I I3 by means of the phase method without mutual interference.

A description will now be given of the operations involved in the process of identifying a subscribers line. the subscriber of line |95 wishes to make a toll call for which a ticket should be prepared to record the nature of the call and the charge therefor. When the subscriber initiates the call, the line finder F finds his line and extends it to the usual pulsing mechanism associated with the selector switch S. The switch S and the sWitch S-I respond successively to the subscribers dial |50 to extend his line to an idle trunk IiJI outgoing in the desired direction. At any suitable time after the extension of the connection of the subscribers line to the trunk IQI an idle one of the identifying mechanisms, such as the mechanism III, is associated with the connection through a connecting device |44. As the subscriber continues to dial the remaining digits of the Wanted designation, these digits may be registered either in the mechanism or in any other suitable registering mechanism where they are later used to control the operation of the switches in the oiiices beyond and also to furnish the necessary information for printing the designation of the called subscribers line.

As soon as the identifying mechanism I II is ready to receive the identification of the calling line |99, the number of which is assumed to be 9090, relay |45 is operated to close a circuit over the established connection for the transmission of impulses of the phase characterizing the identifier IIi. The circuit for these impulses may be traced from the impulse lead |42 through the lamp |46, contacts of relay |45, connector |44 through the circuits |41 of trunk II thence over the sleeve conductor of the established connection through the switches S|, S and F over the sleeve conductor |43 of the calling line through the electrodes of the signal lamp |02 to battery |49. The lamp |92, which is individual to the line lili! and which is located in the lamp panel to represent the four digital values oi the line designation, illuminates in response to each iml pulse received and darkens during the intervals between the impulses. Each light impulse from the lamp |02 is conducted by the plate 2|2 to the exit point 2|5 from whence it shines upon the Assume for this purpose that No. 9 photoelectric cell II9. The cell IIB becomes excited and causes the ow of current from the positive pole of battery III, conductor |5I through the electrodes of the cell IIS, resistor |52 to ground. Each impulse of current flowing through the resistor |52 produces a positive voltage impulse on the No. O thousands conductor 53, and this voltage impulse is applied through the condenser |38 to the control grid |35 of the corresponding tube |20 in the identifier III and similarly to the control grids of the corresponding tubes of all other identifiers I|2, etc. Each impulse applied to the control grid I 35 (and likewise to the control grids of the tubes in the other identifiers) overcomes the negative bias from the batter |54 and raises the positive potentia1 of the control grid. Simultaneously and in the same phase, impulses from the impulse lead |42 are applied through the discharge tube |55 to the primary winding of the common transformer |32 in the identiei` II I. These impulses are induced in the secondary winding of the transformer and apply a positive potential to the suppressor grids 35, IBI of all tubes in the identiiier iii. Since the control and suppressor grids of the single tube |20 in the identier are raised 'at the same instant to a positive potential, the tube becomes conductive to the exclusion of other tubes, and current iiows from the positive pole of battery |56 through the primary winding oi transformer |25, anode I 28, cathode |51 to ground. Each impulse in the primary winding of transformer |26 is induced in the secondary winding and causes the ionization of the control gap of the associated discharge tube |22. Tube |22 transfers its ionization, and current iiows in the main discharge gap from the positive pole of battery, contacts of relay |58, winding of register relay |24, anode and cathode of tube |22 to the negative pole of battery |59. As soon as the tube |22 is fully ionized, the relay |24 operates in the circuit traced and remains energized independently of the control gap of the tube. Thus the signal lamp I t2 individual to the calling line |99 is flashed by impulses of the phase characterizing the identifier I! I, which is associated with the calling line, and the dashing lamp produces impulses of like phase which are applied over the common medium I 3 to the discharge tubes in the identifiers representing the thousands digit of the calling line. However, only the tube I2@ in the identier I|| becomes effective in response to these impulses for the reason that only this tube is receiving impulses of the same phase on its suppressor grid. The result is that the flashing lamp |62 causes the energization of the register relay |24 which represents the thousands digit Value of the calling line in the identiiier I I I, and the corresponding register relay in each of the other identifiers remains inert.

In like manner the flashing lamp |02, through the medium of the hundreds light-conducting plate 225, excites the No. 0 hundreds cell I 59, which in turn causes impulses of like phase to be transmitted over conductor IBI to the control grid of the corresponding hundreds tube in the identifier |I| and to the corresponding tubes in the other identiers. Only the No. 0 hundreds tube in the identifier |II is operated, and in response thereto the corresponding hundreds register relay is energized to register the No, G hundreds digit. Similarly, the ilashing lamp I t2, through the medium of the tens and units lightconducting plates 229 and 246, respectively, causes the excitation of the No. 9 tens cell |52 and the No. units cell |63. The tens cell transmits its impulses to the identiiiers, and the corresponding tens tube and register relay in the identier II I are operated to the exclusion oi the other identifiers. The impulses produced by the No. 0 units cell |63 are applied through the condenser |39 to the control grid |31 of the units tube |2| and similarly to the control grids of the corresponding tubes in the other identiiiers. As explained, only the tube I2I of the identiiier III responds since its suppressor grid I3I is supplied With the same phase as the control grid |31. Accordingly, current flows through the anode-cathode circuit of the tube I2 I, and the impulses induced in the secondary Winding of the transformer I2? cause the ionization of the tube |23, resulting in the operation of the register relay |25 characterizing the units digit "0 of the called line designation.

The four operated register relays |24, |25, may serve in any Well-known manner to cause the printing of 'a ticket to identify the number of the calling line. At any suitable time the relay M5 is released to open the impulse lead and to establish ground connection on the holding conductor extending to the trunk ISI. Also at any suitable time the identifier I|I is fully disconnected from the trunk Ill! by the release of the connecting device |44. The operated register relays |24, |25 and the associated tubes are restored by operating relay |58 to disconnect the supply battery therefrom.

Ii a plurality of subscribers lines, such as the lines |00 and |64, are calling at the same time, it is possible for them all to'make use of the common lamp field for obtaining their several identications therefrom. Line Idil, for example, may seize the idle identier I|I, and line |64 may seize the next idle identifier I I2. Although both identiers are engaged concurrently they operate on different phases, and the lamp |62 individual to line |03 and lamp |63 individual to line |84 ash successively in the appropriate phases to cause 'the operating impulses to be returned to the identiers. Both sets of impulses are returned by the photoelectric cells over the common group of conductors H3 to the identie-rs I I I and I I2 but the phase relation between the impulses makes it possible for the identifiers to receive and register the appropriate designations Without any mutual interference.

What is claimed is:

1. The combination in a signaling system including a group of telephone lines, said lines having designations including a plurality of digital characters Which vary in value from line to line, of a plurality of signal lamps individual respectively to said lines and arrayed in a denite order with respect to the digital characters of said lines, a plurality of identifiers common to said lines, means for connecting calling lines to respective idle identifiers, means for generating impulses of a plurality of different phases, the impulses of the different phases serving individually the different identiers, circuit means controlled by each identier in use for causing the signal lamp of the associated lineY to light in phase with the impulses serving said identifier, photosensitive devices responsive to the lighting of any lamp in said array for producing impulses in phase with the lighting of the lamp and representing the designation of the corresponding line, means for delivering the impulses produced by said photosensitive devices to all oi said identiers, impulse-responsive means in each identier operative When the impulses delivered thereto by said photosensitive devices are of the same phase as the impulses serving vsuch identiner, and means controlled by said impulse-responsive means for identifying the line tovvhich the iden-thier is connected.

2. The combination in a signaling system of a group or" lines, said lines having designations including a plurality of digital characters, of a plurality of signal lamps individual respectively to said lines and arrayed in a `deiinite order With respect to the digital characters of said lines, a plurality or identifiers `commento said lines, means for connecting a plurality of desired lines individually to idle identifiers, the connections between said lines and the respective-identifiers existing concurrently, `means for generating signals of a plurality of different phases, said phases being respectively individual to and characteristic `or said identiers, ycircuit means controlled by each identifier in use for causing the signals of the corresponding phase to'flash the signal lamp of the associated line, light-sensitive devices responsive to the flashing of any lamp in said array for producing signals in phase with the flashing of the lamp and representing the designation of the corresponding line, means for transmitting the signals produced by said lightsensitive devices to vall of said identiiiers, and signal-responsive means in each identifier selectively operated by the signals of the corresponding phase transmitted from said light-sensitive devices to establish the .identity of the'line Ato which such identier is connected.

3. The combination in a signaling system of a group of lines having identifying designations comprising a plurality of digital characters, a

plurality of signal lamps individual respectively to said lines and arranged in a definite order with respect to the digital `characters of said lines, a plurality of identifying mechanisms common .to said lines, means for establishing Aconcurrent connections between desired `lines and said identifying mechanisms, each line being connected to a direrent one .of `said mechanisms, means for producing signal impulses of .a .plurality of different phases, said phases characterizing respectively said identifying mechanisms, circuit means controlled by all identifying mechanisms in concurrent use for flashing the lamps of the associated lines in the different phases characteristic of the corresponding identifying mechanisms, and means in said identifying mechanisms selectively responsive to the nashing of said lamps for establishing in each mechanism the identity of the particular line to which said mechanism is connected.

4. The combination in a signaling system of a group of lines having identifying designations comprising a plurality of digital characters, a plurality of signal lamps individual respectively to said lines and arranged in a denite order with respect to the digital characters of said lines, a plurality of identifying mechanisms common to said lines, means for establishing concurrent connections between desired lines and said identifying mechanisms, each line being connected to a different one of said mechanisms, means for producing signal impulses of a plurality of different phases, said phases characterizing respectively said identifying mechanisms, circuit means controlled by all identifying mechanisms in concurrent use for flashing the lamps of the associated lines in the different phases characteristic of the corresponding identifying mechanisms, light-sensitive devices responsive to the flashng of said lamps for producing impulses of the corresponding phases and characteristic of the designations of the corresponding lines, circuit means connecting said light-sensitive devices in permanent multiple relation with all of said identifying mechanisms, said circut means serving to deliver the impulses of any phase produced by said light-sensitive devices to all of said identifying mechanisms simultaneously, and means in each identifying mechanism selectively responsive to impulses of the phase characterizing said mechanism for establishing the identity of the line to which the mechanism is connected.

5. The combination in a signaling system of a group of lines having designations comprising a plurality of digital characters, a plurality of sig-v nal lamps individual respectively to said lines and arrayed in a denite order with respect to the digital characters of said lines, a plurality of light-sensitive devices representing the different values of the digital characters of said designations, light-conducting means associated with the lamps in said array and serving to conduct the light from any lamp therein to said lightsensitive devices in accordance With the digital values of the designation of the corresponding line, and means controlled by said light-sensitive devices for establishing the designation of the line corresponding to any lighted lamp in said array.

6. rlhe combination in a signaling system of a group of lines having designations comprising a plurality of digital places, the characters in each place varying in value, a plurality of signal lamps individual respectively to said lines and arrayed in a deiinite order with respect to the designations of said lines, a plurality of light-sensitive devices representing the different values of the characters in each digital place of said designations, light-conducting elements, each element associated with the lamps of all lines having like character values in said digital places, said elements serving to conduct the light from any associated lamp to the corresponding light-sensitive device, and means controlled by said lightsensitive devices for establishing the identity of the line corresponding to any lighted lamp in said array.

'7. The combination in a signaling system of a group of lines having designations comprising a plurality of digital places, the characters in each place varying in value, a plurality of signal lamps individual respectively to said lines and arrayed in a denite orderwith respect to the designations of said lines, a plurality of flightsensitive devices representing the different values of the characters in each digital place of said designations, a plurality of plates of light-conducting material, each vplate being common to and disposed in light-conducting relation to the lamps of all lines having the same character value in a particular digital place, each plate also being disposed in light-conducting relation with the light-sensitive device which represents the same character value in the same Vdigital place, said plates serving to conduct the light from any lighted lamp in said array to the lightsensitive devices which represent the designation of the associated line, and means controlled by said light-sensitive devices for establishing the identity of the line.

8. The combination in a signaling system in which the lines of a group have designations comprising a plurality of digital characters of a line identifying mechanism comprising a panel of light-conducting plates having an array of apertures therein, signal lamps disposed Within said apertures, said lamps being individual respectively to the lines of said group and located in said array of apertures in a denite order with respect to the designations of said lines, each of said plates being common to and associated with the lamps of all lines having designation digits of like value, light-sensitive means representing the digital values of said designations, said plates serving to conduct the light from any lamp in said array to the light-sensitive devices representing the designation of the corresponding line, and registering means operated by said light-sensitive devices.

WILLIAM H. T. HOLDEN. 

